It was anything but easy, though. After Azarenka won the first set handily in 28 minutes, the two embarked on a marathon 73-minute second set, with King winning the first three games for a 3-0 lead and even getting to double break point for a 4-0 lead. Azarenka clawed back and eventually pushed it to a tie-break, where King again stormed ahead 3-0, and eventually held a set point leading 6-5.

But the No.2-seeded Azarenka hung on, winning three straight points to edge the American qualifier.

"I think the beginning of the second set wasn't very good for me," Azarenka said after the match. "There were quite a few unforced errors and just really fast mistakes that didn't happen in the first set. It went kind of quickly, but I was glad that I could turn it around there and come back even stronger.

"Then there was competitiveness. She was already in the game and playing at a much higher level than before, and going for her shots. So I had to stay with her and just take my opportunities, and I did.

"There was a little bit of inconsistency today, but first matches can be tricky. I just want to think about what I need to improve for my next match. That's the most important thing for me going forward."

As for the set point, it happens all the time when players go up against top players - the top player comes through on the biggest points. "I always believe that until it's done, you always have a chance," Azarenka, a former World No.1, said. "It doesn't matter what the score is as long as you're trying to do your best, trying to win that point. If the result is different in the end, you know you gave your best.

"I always try to stay in the moment and fight for every ball no matter what the score is."

Azarenka was also asked in her presser about who she enjoys playing most on the tour. And, fittingly, she pointed to the one player who epitomizes fighting for every ball and staying in the moment.

"Oh, that's a tough one. There are so many players that I've played already. But one of my toughest competitions has always been Serena. I feel like our matches make me grow. So I choose her.

"Growth in terms of being a tennis player, pushing my limits, and assessing what you have to do to be at the top of the game. You always take a lot more from losses, and I've lost quite a few to her.